Multiple contact for vertical break switches



n 1 1954 w. P. cowAN MULTIPLE CONTACTFOR VERTICAL BREAK SWITCHES Filed March 18, 1952 IN V EN TOR. W fl [70102627 Patented June I, 1954 MULTIPLE CONTACT FOR VERTICAL BREAK SWITCHES William P. Cowan, McGraw Electric Milwaukee, Wis., assignor to Company, corporation of Delaware Milwaukee, Wis., a

Application March 18, 1952, Serial N 0. 277,141

'7 Claims.

This invention relates to multiple contact for switches and is particularly useful in connection with switches provided for carrying heavy currents.

I The contact points in switches are vital points upon which the entire efiectiveness of the switch depends. If the contact points are too small they bottle-neck the current and cause burning. If the contacts are not tight, sparks and burning result, and when loose the full flow of current is questionable. Thus, it can be understood how important it is on switches carrying heavy current to possess strong and ample contacts.

The object of this invention is to provide additional contact points on a switch blade by placing an inner contact spur through a slot in the switch blade.

Another object of this invention is to provide a staggered line for the contact points so as to lessen the tendency to burn that exists along a direct line.

And another object of this invention is to utilize the pressure action of spring leaves in conjunction with an inner spur pressure to provide an improved contact.

Other objects will appear from time to time in the course of the specification and claims.

I illustrate an embodiment of my invention used on a suitable blade in which:

Fig.- 1 is a fragmentary side elevation of a switch blade using my improved contact means.

Fig. 2 is a section through the switch blade taken outside the spring leaves.

Fig. 3 is a modification of Fig. 2.

Fig. 4 is a top view of the end of the switch blade shown enlarged.

Fig. 5 is a second modification of Fig. 2.

Like reference figures indicate like parts throughout.

In Fig. l, I show a fragmentary view of the type of switching device for which my improved contact device is designed. It is the type of switch for securing a reliable high pressure contact engagement between conductors having a movement relative to each other. It achieves this by a floating pressure member I, and a pressure means 2 which when in operative position relative to each other exert a wiping cam or wedge action thereon so as to effect the required high pressure contact engagement.

The details of this pressure switch can be found in Patent No. 2,231,992 issued February 18, 1941, to Thorsten Fiellstedt. Generally, it consists of two stationaryinsulating stacks 3 and t and a rotatably mounted stack 5. The stack 5 may be 1 2 rotated by any suitable means. Mounted on the stationary stack 4 is the stationary contact assembly comprising U-shaped spring contacts 2 for receiving the flattened contact portion 6 of the switch blade I in high pressure contact engagement. The contact assembly is attached to the support 1 which is secured on the stack 4 and carries the arcing horn 8 and also the terminal clamp means 53 for securing one of the corresponding line conductors. At the end of the contact portion 6 of the switch blade 5 is attached the companion arcing loop I l The other corresponding line conductor has a similar clamping means l0 and these two clamping means 9 and ID are the attachments for installing this device in a circuit.

A frame l2 to which the clamping means Ill is attached is carried at one end by the stationary stack 3. The other end of the frame 12 is made in the form of a stationary bearing l3 which is disposed coaxially with the rotatable stack 5 for journalling the upper end of this stack and the actuating mechanism provided thereon. Integral with this circular bearing [3 and angularly extending therefrom are two arms forming a U-shaped cradle I4 for pivoting the pivot points l5. The pivot points It on each side of the switch blade provide the fulcrum for the rotation of the switch blade I through its arcuate conmeet and disconnect motions with respect to the distantly disposed stationary contacts above stack 4.

The wedging action that takes place when the switch blade is lowered angularly between the pressure spring leaves 2 and then turned to parallel position provides a strong contact at I6 between the outer sides of the switch blade I and the pressure spring 2. This strong contact is extremely vital to the flow of heavy current. It is to intensify and increase the contacts at the place of engagement that I evolved this device. I place a conductor spur I! centrally in front of the spring pressure leaves 2 and attached to the same conductive base. I then provide the flat end S of the switch blade with a slot opening l8 to receive the spur. The slot can be open as shown in Fig. 4 or it can be closed. This slot opening is cut angularly so that it can slide on to the spur as the blade is moved from the angular position to the parallel position and so that when it reaches the parallel position it makes a tight contact with the spur at points l9 and 29. In this manner, my device provides four contact points instead of two and the spur maintains pressure at all the contact points.

There are various modified shapes that the spur and switch blade can take. Fig. 3 illustrates a cone-shape top 2 la on the spur 2|. This provides easy entrance with the switch blade when the slot in the switch blade has a straight out 22 and also provides a tight contact at the lower side 23 of the switch blade.

Fig. utilizes a hollow switch blade 2a with curved sides and the slot 25 out at an angle of about 25. This angular slot 25 allows the switch blade to be turned axially to fit over the spur 26 and slide into tight contact at the upper side 2'! on one side of the spur and at the lower side 28 on the other side of the spur 26.

By positioning the spur in front of the pressure springs Z, the inner contact points are not in line with the outer pressure points and therefore remain cooler than if they were in direct line. This lessens the possibility of burning at the contacts. Silver is used at the contact points on both the blade and the pressure springs to provide a better conductive path.

Therefore, it can be seen that my multiple contact for a switch blade will provide a great improvement where interrupting devices are needed on lines carrying high amperage loads. By providing an increased number of contact points under added pressure, the high amperage can be carried with greater facility and because of the staggered position of the contact points the tendency toward burning is less than if the contacts were in direct line.

I claim:

1. In a switch device comprising a pivot support and a fixed terminal spaced therefrom, the combination with a switch blade mounted on said support for swinging movement relative to said terminal and for rotation about its longitudinal axis substantially coincident with said swinging movement, the swnging end of said blade being flat for high pressure contact ongagement with laterally spaced terminal members and slotted to receive a contact therein, of a U-shaped contact carried by said fixed terminal and comprising spaced resilient arms for receiving said end therebetween, and a spur contact carried by said fixed terminal projecting in a plane coincident with the plane of swinging movement of said blade and oifset from said U-shaped contact in the longitudinal direction of said blade when in closed position, said fiat end of said blade when in closed position having contact areas projecting laterally into high pressure engagement with. said U-shaped contact arms and having contact areas projecting laterally inward of the sides of said slot into high pressure engagement with said spur contact, said blade being rotated into and out of said pressure engagement at the conclusion of and beginning of switch closing and opening operation respectively.

2. In a switch device comprising a pivot sup port and a fixed terminal spaced therefrom, the combination with a switch blade mounted on said support for swinging movement relative to said terminal and for rotation about its longitudinal axis substantially coincident with said swinging movement, the swinging end of said blade being substantially flat for high pressure contact engagement spaced laterally thereof and slotted to receive a contact therein in high pressure contact with the side of said slot, of a U-shaped contact carried by said fixed terminal and comprising spaced resilient arms for receiving said end with terminal members therebetween, and a spur contact carried by said fixed terminal projecting in a plane coincident with the plane of swinging movement of said blades, and having its contact areas in planes paralleling the sides of the slot and in high pressure engagement with said spur contact, said blade being rotated into and out of said pressure engagement at the conclusion of and beginning of switch closing and opening operations respectively.

3. In a switch device comprising a pivot support and a fixed terminal spaced therefrom, the combination with a switch blade mounted on said support for swinging movement relative to said terminal and for rotation about its longitudinal axis substantially coincident with said swinging movement, the swinging end of said blade being substantially flat for high pressure contact engagement with terminal members spaced laterally thereof and slotted to receive a contact therein in high pressure contact with the sides of said slot, of a U-shaped contact carried by said fixed terminal and comprising spaced resilient arms for receiving said end therebetween, and a contact carried by said fixed terminal projecting in a plane coincident with the plane of swinging movement of said blade and offset from said U-shaped contact in the longitudinal direction of said blade when in closed position, said flat end of said blade when in closed position having its contact areas in planes paralleling the sides of the slot and in high pressure engagement with said spur contact, said blade being rotated into and out of said pressure engagement at the conclusion of and beginning of switch closing and opening operations respectively.

4. In a switch device comprising a pivot support and a fixed terminal spaced therefrom, the combination with a switch blade mounted on said support for swinging movement relative to said terminal and for rotation about its longitudinal axis substantially coincident with said swinging movement, the swinging end of said blade having laterally extended contact areas for high pressure engagement with laterally spaced terminal members and slotted to receive a contact therein, of a U-shaped contact carried by said terminal and comprising spaced resilient arms for receiving said end therebetween, and a spur contact carried by said terminal projecting in a plane coincident with the plane of swinging movement of said blade, the end of said blade when in closed position having contact areas projecting laterally into high pressure engagement with said U-shaped contact arms and having contact areas projecting laterally of the sides of said slot into high pressure engagement with said spur contact, said blade being rotated into and out of said pressure engagement at the conclusion of and beginning of switch closing and opening operations respectively.

5. In a switch device comprising a pivot support and a fixed terminal spaced therefrom, the combination of a switch blade mounted on said support for swinging movement relative to said terminal and for rotation about its longitudinal axis substantially coincident with said swinging movement, the swinging end of said blade being substantially fiat and forked at its swinging end, the prongs of said fork each having a contact area extending laterally inward toward the other and adjacent the ends of said prongs and each having a contact area extending laterally outward from the outer margin thereof and adjacent the base thereof, of a U-shaped contact carried by said fixed terminal and comprising spaced resilient arms for receiving said end therebetween, and a spur contact carried by said fixed terminal projecting in a plane coincident with the plane of said swinging movement of said blade and offset from said U-shaped contact in the longitudinal direction of said blade when in closed position, said forked end of said blade when in closed position having its contact areas in high pressure engagement with said U-shaped contact arms and spur, said blade being rotated into and out of said pressure engagement at the conclusion of and beginning of switch closing and opening operations respectively.

6. In a switch device comprising a pivot support and a fixed terminal spaced therefrom, the combination of a switch blade mounted on said support for swinging movement relative to said terminal and for rotation about its longitudinal axis substantially coincident with said swinging movement, the swinging end of said blade being substantially flat and forked at its swinging end, of a U-shaped contact carried by said fixed terminal and comprising spaced resilient arms for receiving said end therebetween, and a spur contact carried by said fixed terminal projecting in a plane coincident with the plane of said swinging movement of said blade and ofiset from said U-shaped contact in the longitudinal direction of said blade when in closed position, said forked end of said blade when in closed position having its contact areas in high pressure engagement with said U-shaped contact arms and spur, said blade being rotated into and out of said pressure engagement at the conclusion of and beginning of switch closing and opening operations respectively.

7. In a switch device comprising a pivot support and a fixed terminal spaced therefrom, the combination of a switch blade mounted on said support for swinging movement relative to said terminal and for rotation about its longitudinal axis substantially coincident with said swinging movement, the swinging end of said blade being substantially fiat and forked at its swinging end, of a U-shaped contact carried by said fixed terminal and comprising spaced resilient arms for receiving said end therebetween, and a spur contact carried by said terminal projecting in a plane coincident with the plane of said swinging movement of said blade, said forked end of said blade when in closed position having its contact areas in high pressure engagement with said U-shaped contact arms and spur, said blade being rotated into and out of said pressure engagement at the conclusion of and beginning of switch closing and opening operations respectively.

References Cited in the file of this patent UNITED STATES PATENTS Number 

